During the oilfield operations, data is typically collected for analysis and/or monitoring of the oilfield operations. Such data may include, for example, subterranean formation, equipment, historical and/or other data. Data concerning the subterranean formation is collected using a variety of sources. Such formation data may be static or dynamic. Static data relates to, for example, formation structure and geological stratigraphy that define the geological structures of the subterranean formation. Dynamic data relates to, for example, fluids flowing through the geologic structures of the subterranean formation over time. Such static and/or dynamic data may be collected to learn more about the formations and the valuable assets contained therein.
Data from one or more wellbores may be analyzed to plan or predict various outcomes at a given wellbore. In some cases, the data from neighboring wellbores, or wellbores with similar conditions or equipment may be used to predict how a well will perform. There are usually a large number of variables and large quantities of data to consider in analyzing oilfield operations. It is, therefore, often useful to model the behavior of the oilfield operation to determine the desired course of action. During the ongoing operations, the operating parameters may adjust as oilfield conditions change and new information is received.
One example aspect of the oilfield operations is acid fracturing. Fractures are often induced hydraulically in low-permeability reservoirs to boost hydrocarbon flow. To fracture the rock, a fluid is injected into the rock at a high pressure. As a result, fractures are induced in stages along the length of a wellbore, creating multiple reservoir zones along the wellbore. Data from the fractured wellbore is then collected and analyzed by an oilfield application to characterize the various reservoirs and completions. Proppant, such as sand of a particular size, is sometimes injected into the fracture to keep it open and enhance hydrocarbon flow into the wellbore. Acid treatments may also be used to enhance the fracturing operation. For example, a hydraulic fracturing may be performed in carbonate formations to etch the open faces of induced fractures using a hydrochloric acid treatment. When the treatment is complete and the fracture closes, the etched surface provides a high conductivity path from the reservoir to the wellbore. Other acid commonly used in the treatments includes acetic acid, formic acid, fluoboric acid, or a range of acid types or acid blends.
While hydraulic fracturing using non-reactive fracturing fluid and/or proppant may be modeled using mass conservation equations and continuity equations, acid fracturing mechanisms are not understood with the same level of accuracy due to uncertain downhole conditions of varying geometry associated with acid induced effects as well as parameters that are poorly controlled during typical acid treatments. In addition, production decline of a wellsite is difficult, if not impossible to forecast.